Retardation conductor for variable field electronic tubes or the like



Feb. 16, 1960 w. EICHIN 2,925,557

RETARDATION CONDUCTOR FOR VA BLE FIELD ELECTRONIC TUBES 0R YT KE Filed May 9, 1955 2 Sheets-Sheet 1 fiyerzfars.

Feb. 16, 1960 w, E m- N ETAL 2,925,567

RETARDATION CONDUCTOR FOR VARIABLE FIELD ELECTRONIC TUBES OR THE LIKE Filed May 9, 1955 2 Sheets-Sheet 2 JFZZ/eI ZarET. WarzzarflZaZ/rg 4? Werner 742.45%.

States RETARDATION CONDUCTOR FOR VARIABLE FIELD ELECTRONIC TUBES OR THE LIKE Werner Eichin and Werner Veith, Munich, Germany, assignors to Siemens & Halslre Ahtiengesellschaft, Munich, Germany, a corporation of Germany This invention is concerned with a conductor forming a delay line of spiral-like, meandering or similar shape which is suitable for variable field electronic tubes or the like.

The object of the invention is to provide a delay line in which the stored highfrequency energy is as low as possible and the use of which avoids detrimental capacitances as far as possible.

The invention is of importance in all cases wherein customary spiral-shaped delay lines would assume unfavorable proportions or dimensions that could not be very well realized in practice.

The delay line according to the invention provides for each turn one or more portions which extend or are positioned in the region correlated with one or more electron fiows and wherein the turns extend in such a manner that the capacitances of the conductor portions lie substantially exclusively within the region of energy interchange with the electron flow or flows.

The line portions lying outside of the region of energy interchange may be shaped arcuately, for example, circularly or elliptically. The cross-sectional configuration may suitably correspond to the outline of a dumbbell.

It is in connection with such configuration of advantage to,

displace at least the portions lying outside the region of energy exchange from turn to turn angularly relative to one another. The entire delay line may be made of a single integral wire or ribbonlike element.

The various objects and features of the invention will appear from the description which will be rendered below with reference to the accompanying drawings. In these drawings,

Fig. 1 shows how a wire or like conductor element may be wound to form the delay line in one embodiment thereof;

Fig. 2 illustrates the conductor element of Fig. 1 diagrammatically with its turns expanded and placed relative to the path of the electrons;

Fig. 3 indicates the conductor of Fig. 2 after the individual conductor loops have been mutually angularly displaced;

Fig. 4 is a diagram showing a section perpendicular to the electron flow so as to explain the field distribution and the correlation between the electric fields and the electron flow; and

Figs. 5 and 6 show conductor elements wound in a manner differing from that shown in Fig. 2, to form conductor portions neighboring on the electron flow,

As indicated diagrammatically in Fig. 1, the conductor element, a suitable wire or ribbon, may be wound in successive adjacent turns or layers on a suitable mandrel 2 forming the outline of a dumbbell. After removal of the wound turns from the mandrel, they may be expanded to produce, in the case of a ribbonlike element, a delay line diagrammatically indicated in Fig. 2. The placement of the turns as shown in Fig. 2, does not conform to the final shape because the expansion of the wound conductor results in a mutual angular displacement of the atent individual turns due to the elastic tension of the material. The mutual angular relationship of the turns as it results after expansion of the wound conductor is apparent from Fig. 3, showing the turns as seen, for example, when looking at the conductor in axial direction from one end thereof.

As will be apparent from Fig. 3, there will result an inner space 3 for the electron flow 9 indicated in Figs. 2 and 4. The turns of the conductor are suitably dimensioned so that one whole turn corresponds substantially to the wave length chosen for the pass range.

The spiral-like or meandering structure may be considered to constitute a line comprising successively disposed alternately capacit'atively and inductively loaded portions. The inductance appears mainly along the loop portions 4 (Fig. 2) while the capacitance appears between the wire or ribbon conductor portions 5 and 6 (Fig. 2) which are nearest to the electron flow.

As mentioned before, Fig. 4 illustrates in schematic manner a section perpendicular to the electron flow to show the field distribution and the correlation between the electric fields and the electron flow. Numerals 5 and 6 indicate in' conformance with Fig. 2 conductor portions, in section, which lie nearest to the electron flow. The conductor portions lit and 11 are shown in similar manner. The illustration shows that, assuming proper dimensioning, the electric high-frequency field will extend across the space 3 (Fig. 3) which is permeated by the electron flow 9, with opposite phase between the conductor portions 5, 6, 1t) and 11, so that the entire space is uniformly permeated by the high-frequency field.

The line according to the invention comprises spatially separate inductance and capacitance elements. The individual loops may be to a far-reaching extent capacitively coupled by the mutual angular displacement indicated in Fig. 3. Practically no capacitances will in this manner arise with the exception of those caused by the highfrequency field which is required for the coupling.

The delay conductor portions extending between the loops may be slightly bent outwardly at the exit areas for the electron beam so as to assure a more favorable matching to a cross-sectionally circular electron flow. The portions 12 and 13 of Fig. 1 may for this purpose be formed suitably outwardly bulging.

Figs. 5 and 6 show further embodiments of the invention in a manner analogous to Fig. 2. According to Fig. 5, a conductor may be wound to form turns resembling a large circle merging with a smaller circle; according to Fig. 6, a conductor may be wound to form turns comprising circular sections interconnected by straight sections defining a central space. The respective conductor wound as described is thereafter expanded (just as'in case of the conductor illustrated in Figs. 1 to 3) to form a meandering delay line surrounding a central space for the electron fiow. The length of the loops 7 and 8, shown respectively in Figs. 5 and 6, may be dimensioned so as to correspond substantially to one-half of the operating frequency.

Modifications as to the configuration of the delay conductor are possible especially for cases providing for several electron flows instead of one single flow or beam.

Changes may accordingly be made within the scope and spirit of the appended claims.

We claim:

1. A delay line adapted for use with variable field electron tubes, comprising a conductor formed from a continuous, elongated member wound in meandering spirally extending turns disposed about a central area traversed by an electron stream and having only a part of each turn disposed within a region otenergy interchange between the electron stream and the electromagnetic wave carried by said conductor, portions of said turns having opposite phase relationships being disposed close to said central area in an opposed relation and thereby forming a large capacitance and other portions of said turns being disposed outside of said central area and constituting inductances and forming with neighboring corresponding conductor portions relatively small capacitances.

2. A delay line according to claim 1, wherein said other portions of said turns are arcuately shaped.

3. A delay line according to claim 1, wherein said other portions of said turns are shaped to describe circular outlines.

4. A delay line according to claim 1, wherein said other portions of said turns are shaped to describe elliptical outlines.

5. A delay line according to claim 1, wherein at least one of said turns describes an outline corresponding substantially to the outline of a dumbbell.

6. A delay line according to claim 1, wherein said turns are angularly displaced one with respect to the other.

7. A delay line according to claim 1, wherein the length of said other portions of said turns corresponds approximately to one-half of the Wave length of the operating frequency.

8. A delay line according to claim 1, wherein said other portions of said turns extend in the manner of loops, the length of each loop corresponding approximately to one-half of the wave length of the operating frequency.

References Cited in the file of this patent UNITED STATES PATENTS Re. 21,739 Llewellyn Mar. 4, 1941 2,566,087 Lerbs Aug. 28, 1951 2,802,135 Dodds Aug. 6, 1957 FOREIGN PATENTS 955,557 France June 27, 1949 668,017 Great Britain Mar. 12, 1952 1,025,094 France Jan. 21, 1953 1,074,017 France Mar. 31, 1954 

